From 8ca6ca87fdbfee3d60628df4ca0ed08877ad8895 Mon Sep 17 00:00:00 2001
From: Yaacov Akiba Slama <ya@slamail.org>
Date: Fri, 19 Mar 2021 13:47:36 +0200
Subject: [PATCH] Synchronize private channels from lnd to the channels table
 every hour

---
 db.go                 |  3 ++-
 forwarding_history.go | 35 +++++++++++++++++++++++++++++++++++
 server.go             |  1 +
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/db.go b/db.go
index f28f883..a2aeec5 100644
--- a/db.go
+++ b/db.go
@@ -74,7 +74,8 @@ func insertChannel(chanID uint64, channelPoint string, nodeID []byte) error {
 	_, err := pgxPool.Exec(context.Background(),
 		`INSERT INTO
 	channels (chanid, channel_point, nodeid)
-	VALUES ($1, $2, $3)`,
+	VALUES ($1, $2, $3)
+	ON CONFLICT (chanid) DO NOTHING`,
 		chanID, channelPoint, nodeID)
 	if err != nil {
 		return fmt.Errorf("insertChannel(%v, %s, %x) error: %w",
diff --git a/forwarding_history.go b/forwarding_history.go
index 5ee298f..48bc35d 100644
--- a/forwarding_history.go
+++ b/forwarding_history.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"encoding/hex"
 	"fmt"
 	"log"
 	"os"
@@ -35,6 +36,40 @@ func (cfe *copyFromEvents) Err() error {
 	return cfe.err
 }
 
+func channelsSynchronize() {
+	for {
+		err := channelsSynchronizeOnce()
+		log.Printf("channelsSynchronizeOnce() err: %v", err)
+		time.Sleep(1 * time.Hour)
+	}
+}
+
+func channelsSynchronizeOnce() error {
+	log.Printf("channelsSynchronizeOnce - begin")
+	clientCtx := metadata.AppendToOutgoingContext(context.Background(), "macaroon", os.Getenv("LND_MACAROON_HEX"))
+	channels, err := client.ListChannels(clientCtx, &lnrpc.ListChannelsRequest{PrivateOnly: true})
+	if err != nil {
+		log.Printf("ListChannels error: %v", err)
+		return fmt.Errorf("client.ListChannels() error: %w", err)
+	}
+	log.Printf("channelsSynchronizeOnce - received channels")
+	for _, c := range channels.Channels {
+		nodeID, err := hex.DecodeString(c.RemotePubkey)
+		if err != nil {
+			log.Printf("hex.DecodeString in channelsSynchronizeOnce error: %v", err)
+			continue
+		}
+		err = insertChannel(c.ChanId, c.ChannelPoint, nodeID)
+		if err != nil {
+			log.Printf("insertChannel(%v, %v, %x) in channelsSynchronizeOnce error: %v", c.ChanId, c.ChannelPoint, nodeID, err)
+			continue
+		}
+	}
+	log.Printf("channelsSynchronizeOnce - done")
+
+	return nil
+}
+
 func forwardingHistorySynchronize() {
 	for {
 		err := forwardingHistorySynchronizeOnce()
diff --git a/server.go b/server.go
index 89b01ee..ec6cba0 100644
--- a/server.go
+++ b/server.go
@@ -379,6 +379,7 @@ func main() {
 	go intercept()
 
 	go forwardingHistorySynchronize()
+	go channelsSynchronize()
 
 	s := grpc.NewServer(
 		grpc_middleware.WithUnaryServerChain(func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {